The invention relates to an electrical connector and more specifically to one that can be locked onto either a male electrical terminal or a female electrical terminal.
Extension cords have been used for many years to lengthen the cord of an electrical device so that it can be connected to a remote power supply or receptacle. One end of the extension cord has a female socket that is sized to engage with a plug located on the cord of the electrical device while the other end of the extension cord is formed with a plug which is adapted to engage with a socket located at the power supply.
Quite often, while the user is moving the electrical device or when the extension cord or the cord of the device becomes entangled or caught, the extension cord will become disconnected from the device or the power supply. When this occurs, the user is forced to discontinue operations and to reestablish the electrical connection, thereby adding additional time to complete the task. Another problem is that the extension cord partially disconnects from the receptacle and has hot electrical contacts exposed to the user and the environment. In this situation, a person may accidently touch the electrical contact and sustain injuries or the electrical contacts may short and cause a fire and/or damage to the device, power supply or user.
In order to prevent the extension cord from becoming disconnected from the electrical device, users have often resorted to means such as tying a knot in the cord of the device and the socket end of the extension cord to isolate the plug/socket connection from induced stress. This method, is time consuming, and can damage the insulation surrounding the conductor, and shortens the effective life of the cord.
To overcome the above disadvantages, extension cords have been designed with a variety of locking mechanisms to securely connect the extension cord to the device or power supply. One such extension cord is shown in U.S. Pat. No. 4,085,991. It utilizes structure allowing engagement of the apertures formed in the prongs of a male electrical plug. Once engaged, the two members cannot be pulled apart and there is structure for releasing that engagement. A similar method of locking a connector onto the male prong of a male electrical plug is illustrated in U.S. Pat. No. 5,352,132.
Other prior art patents of interest are the following. The Chesler U.S. Pat. No. 3,691,327 discloses a circuit-closing adaptor having a key-operated lock means that closes the electrical circuit when the key is in the lock and which opens the circuit when the key is removed from the lock.
The Sherman U.S. Pat. No. 4,167,658 is directed to an electrical lock having a housing carrying a pair of prongs to be mounted in a conventional wall socket. It has a key operated cam in the housing that makes and breaks one of the contacts and latching means carried by that contact that mechanically locks onto the plug prong. The Solomon U.S. Pat. No. 4,579,410 is directed to a security attachment for an electrical plug that is effective to prevent unauthorized use and to readily permit authorized use.
The Windsor Jr. U.S. Pat. No. 4,875,874 is directed to a rotatable electrical connector arrangement for the secure snag free interlocking of the socket female end member of an electrical power extension cord, to the plug or male end member of an electrical power implement, or to any related device having a male plug member fixed to its power cord. The Torok U.S. Pat. No. 5,108,301 is directed to a locking electrical cord connector that securely attaches at both the male and female ends.
It is an object of the invention to provide a novel lockable electrical cord connector unit that can be installed on the end of the electrical cord of an electrical device.
It is also an object of the invention to provide a novel lockable electrical cord connector unit that will prevent accidental disconnection.
It is another object of the invention to provide a novel lockable electrical cord connector unit that will prevent downtime previously caused by the electrical connections pulling apart.
It is an additional object of the invention to provide a novel lockable electrical cord connector unit that will reduce the cost of labor caused by downtime delays.
It is a further object of the invention to provide a novel lockable electrical cord connector unit that is easy and fast to install.
It is also an object of the invention to provide a novel lockable electrical cord connector unit that is inexpensive to manufacture and market.
It is another object of the invention to provide a novel lockable electrical cord connector unit that is safer since it prevents partial disconnection and exposed contacts.
It is also an object of the invention to provide a novel lockable electrical cord connector unit that will prevent the possibility of an electrical short that could cause a fire.
The lockable electrical cord connector unit has been designed with a basic component, an elongated cylindrical connector housing having a front wall structured as a female electrical terminal or as a male electrical terminal. The rear wall of the connector housing can have either a bore hole for receiving the end of an extension cord or it can be structured as a male electrical terminal. A substantially semi-circular groove extends around the outside of the bottom half of the connector housing to opposing positions near its mid point. A cylindrical bore extends inwardly from the front wall of the connector housing and extends a substantial portion of the length of the connector housing and in some cases its entire length. A ground cylinder is telescopically received in the cylindrical bore. An eccentric control pin has its front end connected to the ground cylinder and its rear end is connected to a control pin guide that is attached to the inner surface of a locking control ring that telescopes over the connector housing. The locking control ring can be rotated through a range of approximately 180 degrees which would cause the ground cylinder to rotate at the same time. When the connector housing has the mating male and female wedge structure incorporated in its interior, a male electrical plug that has been inserted into the front end of the connector housing can be locked in its female socket by the rotation of the locking control ring in one direction and it may be released by rotation in the opposite direction. Where a male electrical structure is either extending from the front wall or the rear wall of the connector housing, the rotation of the locking control ring will cause the ground pin to be rotated in such a manner that it will lock into a ground receptacle into which it has been inserted.
Utilizing the basic connector housing structure and the locking control ring, one embodiment of the lockable electrical cord connector unit can have its rear end connected to an extension cord and its front end structured as a female receptacle for a male electrical terminal plug. Using the same basic connector housing and the locking control ring structure, a second embodiment can be assembled with an extension cord connected to its rear end and its front end can be structured with projecting male conductor blades and a ground pin. A third embodiment using the same basic connector housing structure and the locking control ring can be produced in the form of an adaptor having a female front end and a male rear end. The exact manner in which the different embodiments function is fully described later in the specification.